Method and apparatus for electron beam lithography

Abstract

A system using an energy beam to expose patterns on a wafer includes first mirror elements, a multiplexer element, and second mirror elements. The first and second mirror elements are dynamically controlled to reflect the energy beam to the wafer. The first mirror elements are configured in a first chain having a first data input and a first data output. The multiplexer element includes a second data input, a third data input, a select input, and a second data output. The third data input is coupled to the first data output. The second mirror elements are configured in a second chain having a fourth data input.

What is claimed is: 
     
       1. A system using an energy beam to expose patterns on a wafer, comprising:
 a first plurality of mirror elements; and 
 a second plurality of mirror elements; 
 wherein: 
 the first plurality of mirror elements is configured to expose the wafer using the energy beam; and 
 the second plurality of mirror elements is configured to substitute the first plurality when at least one mirror element of the first plurality is found defective. 
 
     
     
       2. The system of  claim 1 , wherein the energy beam is an electron beam. 
     
     
       3. The system of  claim 1 , further comprising a first device for deactivating the first plurality of mirror elements. 
     
     
       4. The system of  claim 3 , further comprising a select input for selecting the first plurality of mirror elements to be used for exposing the wafer, wherein the first device is coupled to the select input. 
     
     
       5. The system of  claim 4 , wherein:
 one of the first plurality of mirror elements is defective; 
 the first plurality of mirror elements are deactivated by the first device; and 
 the select input is set to a value such that the first plurality of mirror elements is not selected for exposing the wafer. 
 
     
     
       6. The system of  claim 1 , wherein:
 the number of mirror elements in the second plurality is an integer multiple of the number of mirror elements in the first plurality. 
 
     
     
       7. The system of  claim 1 , wherein the first plurality of mirror elements are configured in a bidirectional shifting chain. 
     
     
       8. The system of  claim 1 , further comprising:
 a third plurality of mirror elements, the third plurality of mirror elements being dynamically controlled to reflect the energy beam to the wafer; and 
 a multiplexer, a data input of the multiplexer being coupled to an output of the first plurality, and an output of the multiplexer being coupled to an input of the third plurality. 
 
     
     
       9. A method of manufacturing a wafer with an integrated circuit (IC) layout using an electron beam (e-beam) writing system that includes a first plurality of e-beam mirrors, the method comprising the steps of:
 diagnosing the first plurality for defects; and 
 upon a condition in which at least one defective e-beam mirror is found, bypassing a portion of the first plurality including the at least one defective e-beam mirror. 
 
     
     
       10. The method of  claim 9 , further comprising locating the defective e-beam mirror. 
     
     
       11. The method of  claim 10 , wherein the e-beam mirrors include a shift chain, and wherein the locating the defective e-beam mirror includes shifting data in and out of the shift chain. 
     
     
       12. The method of  claim 9 , wherein the first plurality of e-beam mirrors are configured into a first shift chain, the first shift chain having a first end and a second end, the first shift chain being capable of bidirectional shifting between the first end and the second end. 
     
     
       13. The method of  claim 9 , further comprising:
 deactivating the bypassed e-beam mirrors. 
 
     
     
       14. The method of  claim 9 , wherein the e-beam writing system further includes a second plurality of e-beam mirrors, further comprising: substituting a portion of the second plurality for the bypassed e-beam mirrors. 
     
     
       15. The method of  claim 14 , further comprising:
 exposing the wafer using a portion of the first plurality that is not bypassed; and 
 exposing the wafer using the portion of the second plurality. 
 
     
     
       16. The method of  claim 15 , wherein the portion of the second plurality includes the same number of e-beam mirrors as the bypassed e-beam mirrors. 
     
     
       17. A system comprising:
 a wafer; 
 an electron beam; 
 a first plurality of mirror elements configured to expose the wafer using the electron beam; and 
 a second plurality of mirror elements configured to substitute for the first plurality of mirror elements when at least one mirror element of the first plurality of mirror elements is defective. 
 
     
     
       18. The system of  claim 17 , further comprising a first device for deactivating the first plurality of mirror elements. 
     
     
       19. The system of  claim 18 , further comprising a select input for selecting the first plurality of mirror elements to be used for exposing the wafer, wherein the first device is coupled to the select input. 
     
     
       20. The system of  claim 19 , wherein:
 one of the first plurality of mirror elements is defective; 
 the first plurality of mirror elements is deactivated by the first device; and 
 the select input is set to a value indicating that the first plurality of mirror elements is not selected for exposing the wafer.